Magnetic resonance imaging (MRI) systems have a broad range of uses in the medical field. An MRI system contains many system components that generate heat at high power, such as the cold head compressor, gradient coils (GC), gradient power amplifier (GPA), and radio frequency power amplifier (RFPA). A cooling system is generally needed to cool these system components that generate heat at high power.
FIG. 1 is an existing cooling device for an MRI device. As FIG. 1 shows, a first pump 4 supplies cooling water at a low temperature to a pipeline for cooling an MRI device M, to absorb heat generated during operation of the MRI device. After heating up, the cooling water is sent into an evaporator 8 and undergoes heat exchange with a refrigerant in the evaporator, experiences a drop in temperature, and is sent to the first pump 4 again. Having turned into vapor due to a temperature increase caused by the heat exchange in the evaporator 8, the refrigerant is compressed to form a vapor at high temperature and high pressure in the compressor 5, and discharged into a condenser 10. In the condenser 10, the vapor releases heat to a cooling medium, condensing to form a high-pressure liquid, before passing through an expansion valve 9 to become a refrigerant at low pressure and low temperature. In the condenser 10, water that has heated up through heat exchange with the refrigerant is sent to a pump 6, and undergoes a cooling treatment by a fan 7 before being sent back to the condenser 10. However, in such a cooling device, it is generally necessary to operate the compressor, pump and fan continuously, so the amount of energy consumed is quite large. Moreover, in the case of certain MRI systems that switch back and forth between high-load operation and low-load operation, the water supply temperature in the cooling device will experience large fluctuations, with the result that the stability of the water-cooled MRI systems is affected.